c - 从 C 中的字符串中提取整数

Question

我正在尝试从字符串 add 56 89 29 中提取所有数字。我的代码有问题，我无法弄清楚。输出如下所示:

Current no: 56
Current no: 89
Current no: 9
Current no: 29
Current no: 9
Current no: 9
Current no: 0
Current no: 0

我希望这样:

Current no: 56
Current no: 89
Current no: 29
Current no: 29
Current no: 29
Current no: 29

有更好的方法可以做到这一点，但我想知道这个实现有什么问题。

#include <string.h>
#include <stdio.h>

int main(int argc, char * argv[]){
    char temp[100];
    char op[3];
    char *buf = "add 56 89 29";
    int offset = 0;
    int rcount = 0;
    int lastno = -999;
    int currno;
    bzero(&temp, sizeof(temp));
    sscanf(buf, "%s", op);  // Get the operator (add)
    if(!strcmp(op, "add")){
        while(1){
            sscanf(buf + offset + 4, "%s", temp);  // strlen("add ") == 4
            currno = atoi(temp);
            offset += strlen(temp);
            if(currno == lastno){
                rcount++;
                // Repeating numbers means string finished
                if(rcount == 3){
                    break;
                }
            }
            printf("Current no: %d\tOffset: %d\n", currno, offset + 4);
            lastno = currno;
        }
    }
    return 0;
}

提前致谢!

Answer 1

"%n" 说明符将记录一次扫描使用的字符数。可以将结果添加到偏移量以在字符串中前进。

#include <string.h>
#include <stdio.h>

int main(int argc, char * argv[]){
    char temp[100];
    char op[4];
    char *buf = "add 56 89 29";
    int offset = 0;
    int used = 0;
    int rcount = 0;
    int lastno = -999;
    int currno;
    bzero(&temp, sizeof(temp));
    sscanf(buf, "%3s%n", op, &used);  // Get the operator (add)
    offset += used;
    if(!strcmp(op, "add")){
        while( ( sscanf(buf + offset, "%99s%n", temp, &used)) == 1) {
            currno = atoi(temp);
            offset += used;
            printf("Current no: %d\tOffset: %d\n", currno, offset);
            lastno = currno;
        }
    }
    return 0;
}