ObjC语法练习 冒泡排序选择排序矩阵相乘

Posted 2020-06-09

用OC实现的冒泡排序、选择排序、矩阵相乘，纯粹是用来练习语法。

冒泡排序，程序如下：

void bubbleSort()
{
    //初始化数组
    NSMutableArray *array1 = [[NSMutableArray alloc] initWithCapacity:8];
    [array1 addObject:@"5"];
    [array1 addObject:@"10"];
    [array1 addObject:@"8"];
    [array1 addObject:@"12"];
    [array1 addObject:@"9"];
    [array1 addObject:@"4"];
    [array1 addObject:@"20"];
    [array1 addObject:@"14"];
    
    NSInteger count = array1.count;
    
    for(int i = 0; i < count; ++i){
        for(int j = 0; j < count - i - 1; ++j){
            NSInteger before = [[array1 objectAtIndex:j] integerValue];
            NSInteger after = [[array1 objectAtIndex:j + 1] integerValue];
            if(before > after){
                NSInteger temp = before;
                [array1 setObject:[NSString stringWithFormat:@"%ld", after] atIndexedSubscript:j];
                [array1 setObject:[NSString stringWithFormat:@"%ld",temp ] atIndexedSubscript:j + 1];
            }
        }
    }
    
    for(int i = 0; i < count; ++i){
        NSLog(@"%@",[array1 objectAtIndex:i]);
    }
}

选择排序，程序如下：

void selectSort()
{
    //初始化数组
    NSMutableArray *array1 = [[NSMutableArray alloc] initWithCapacity:8];
    [array1 addObject:@"5"];
    [array1 addObject:@"10"];
    [array1 addObject:@"8"];
    [array1 addObject:@"12"];
    [array1 addObject:@"9"];
    [array1 addObject:@"4"];
    [array1 addObject:@"20"];
    [array1 addObject:@"14"];
    
    NSInteger count = array1.count;
    
    for(int i = 0; i < count - 1; ++i){
        NSInteger min = i;
        for(int j = i + 1; j < count; ++j){
            NSInteger minNum = [[array1 objectAtIndex:min] integerValue];
            NSInteger num = [[array1 objectAtIndex:j] integerValue];
            if(minNum > num){
                min = j;
            }
        }
        NSInteger changeNum = [[array1 objectAtIndex:min] integerValue];
        NSInteger temp = [[array1 objectAtIndex:i] integerValue];
        [array1 setObject:[NSString stringWithFormat:@"%ld",changeNum] atIndexedSubscript:i];
        [array1 setObject:[NSString stringWithFormat:@"%ld",temp] atIndexedSubscript:min];
    }
    
    for(int i = 0; i < count; ++i){
        NSLog(@"%@",[array1 objectAtIndex:i]);
    }
}

矩阵相乘，程序如下：

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        
        //bubbleSort();
        //selectSort();
        
        //矩阵相乘
        //初始化矩阵1,矩阵1为：
        //    1   0   2
        //    -1  3   1
        NSMutableArray *array1 = [[NSMutableArray alloc] initWithCapacity:2];
        NSMutableArray *row1 = [[NSMutableArray alloc] initWithCapacity:3];
        NSMutableArray *row2 = [[NSMutableArray alloc] initWithCapacity:3];
        [row1 addObject:@"1"];
        [row1 addObject:@"0"];
        [row1 addObject:@"2"];
        [row2 addObject:@"-1"];
        [row2 addObject:@"3"];
        [row2 addObject:@"1"];
        [array1 addObject:row1];
        [array1 addObject:row2];
        //初始化矩阵2,矩阵2为
        //   3    1
        //   2    1
        //   1    0
        NSMutableArray *array2 = [[NSMutableArray alloc] initWithCapacity:3];
        NSMutableArray *newrow1 = [[NSMutableArray alloc] initWithCapacity:2];
        NSMutableArray *newrow2 = [[NSMutableArray alloc] initWithCapacity:2];
        NSMutableArray *newrow3 = [[NSMutableArray alloc] initWithCapacity:2];
        [newrow1 addObject:@"3"];
        [newrow1 addObject:@"1"];
        [newrow2 addObject:@"2"];
        [newrow2 addObject:@"1"];
        [newrow3 addObject:@"1"];
        [newrow3 addObject:@"0"];
        [array2 addObject:newrow1];
        [array2 addObject:newrow2];
        [array2 addObject:newrow3];
        
        //第一个矩阵的行数
        NSInteger numRow1 = array1.count;
        //第一个矩阵的列数
        NSArray  *Col = [array1 objectAtIndex:0];
        NSInteger numCol1 = Col.count;
        NSLog(@"numRow1 = %ld",numRow1);
        NSLog(@"numCol1 = %ld",numCol1);
        
        //第二个矩阵的列
        NSArray *Col2 = [array2 objectAtIndex:0];
        NSInteger numCol2 = Col2.count;
        NSLog(@"numCol2 = %ld",numCol2);
        
        NSMutableArray *array3 = [[NSMutableArray alloc] initWithCapacity:numRow1];
        //开始矩阵相乘
        for(int i = 0; i < numRow1; ++i){
            NSMutableArray *temprow = [[NSMutableArray alloc] initWithCapacity:numCol2];
            for(int j = 0; j < numCol2; ++j){
                NSInteger sum = 0;
                for(int k = 0; k < numCol1; ++k){
                    NSInteger num1 = [[[array1 objectAtIndex:i] objectAtIndex:k] intValue];
                    NSInteger num2 = [[[array2 objectAtIndex:k] objectAtIndex:j] intValue];
                    sum = sum + (num1 * num2);
                }
                NSString *tempString = [NSString stringWithFormat:@"%ld",sum ];
                [temprow addObject:tempString];
            }
            [array3 addObject:temprow];
        }
        for(int i = 0; i < numRow1;++i){
            for(int j = 0; j < numCol2; ++j){
                NSLog(@"%@",[[array3 objectAtIndex:i] objectAtIndex:j]);
            }
        }
    }
    return 0;
}