C++字符串替换函数

string_repalce.cpp

// 参考《C++编程思想卷2》

#include <iostream>
#include <string>

using namespace std;

string& replace_all(string& context, const string& from, const string& to) {
    size_t look_here = 0;
    size_t found_here;
    while ((found_here = context.find(from, look_here)) != string::npos) {
        context.replace(found_here, from.size(), to);
        look_here = found_here + to.size();
    }
    return context;
}

void test(string s, string from, string to, string result) {
    string ret = replace_all(s, from, to);
    if (ret != result) {
        cout << "fail case:" << endl;
        cout << s << " " << from << " " << to << endl;
        cout << "true: " << result << endl;
        cout << "false: " << ret << endl;
        cout << "--------------" << endl << endl;
    }
}

int main()
{
    test("", "a", "b", ""); // empty
    test("ab", "a", "b", "bb"); // equal repalce
    test("abcdabd", "abc", "xf", "xfdabd"); // short repalce
    test("xabcdabd", "ab", "AB", "xABcdABd"); // equal, down to upper
    test("abcd", "xy", "z", "abcd"); // not find
    test("abcdabd", "ab", "xyzab", "xyzabcdxyzabd"); // add same substring
}