UC知道C语言中怎么判定输入是否为空
来源：百度知道 编辑：UC知道 时间：2024/07/08 11:00:36
原题如下
Calculate a + b
Input
The input will consist of a series of pairs of integers a and b,separated by a space, one pair of integers per line.
Output
For each pair of input integers a and b you should output the sum of a and b in one line,and with one line of output for each line in input.
Sample Input
1 5
Sample Output
6
Hint:
Q:Where is the input and the output?
A:Your program shall read input from stdin('Standard Input') and write output to stdout('Standard Output').For example,you can use 'scanf' in C or 'cin' in C++ to read from stdin,and use 'printf' in C or 'cout' in C++ to write to stdout.
User programs are not allowed to open and read from/write to files, you will get a "Runtime Error" if you try to do so.
不行...提交了答案还是提示Runtime Error
Calculate a + b
Input
The input will consist of a series of pairs of integers a and b,separated by a space, one pair of integers per line.
Output
For each pair of input integers a and b you should output the sum of a and b in one line,and with one line of output for each line in input.
Sample Input
1 5
Sample Output
6
Hint:
Q:Where is the input and the output?
A:Your program shall read input from stdin('Standard Input') and write output to stdout('Standard Output').For example,you can use 'scanf' in C or 'cin' in C++ to read from stdin,and use 'printf' in C or 'cout' in C++ to write to stdout.
User programs are not allowed to open and read from/write to files, you will get a "Runtime Error" if you try to do so.
不行...提交了答案还是提示Runtime Error
ACM吧
#include <iostream>
#incldue <cstdlib>
using namespace std;
int main()
{
int a,b;
while(cin>>a>>b)
cout<<a+b<<endl;
}
就行了
或者while里改成
while((scanf(%d %d,&a,&b))!=EOF)
scanf()里规定了输入两个数之间是空格
而用cin可以不用管 c++的io流很强大 不需要做这种考虑
但是scanf明显比cin快
1.使用strlen函数来判断输入是否为空，如果返回值为0，就是空。
strlen做的是一个计数器的工作，它从内存的某个位置（可以是字符串开头，中间某个位置，甚至是某个不确定的内存区域）开始扫描，直到碰到第一个字符串结束符'\0'为止，然后返回计数器值(长度不包含“\0”)。
原 型：extern unsigned int strlen(char *s）;
头文件：string.h
格 式：strlen （字符数组名）
功 能：计算字符串s的（unsigned int型）长度，不包括'\0'在内
说 明：返回s的长度，不包括结束符NULL。
2.例程：
#include <stdio.h>
#include <string.h>
int main(){
char s[1000];
while (gets(