| I/O manipulators | ||||
| Print functions(C++23) | ||||
| C-style I/O | ||||
| Buffers | ||||
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| Streams | ||||
| Abstractions | ||||
| File I/O | ||||
| String I/O | ||||
| Array I/O | ||||
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(C++23) | ||||
(C++23) | ||||
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| Synchronized Output | ||||
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| Types | ||||
| Error category interface | ||||
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Defined in header <cstdio> | ||
char* gets(char* str); | (deprecated in C++11) (removed in C++14) | |
Readsstdin into given character string until a newline character is found or end-of-file occurs.
Contents |
| str | - | character string to be written |
str on success, a null pointer on failure.
If the failure has been caused by end of file condition, additionally sets theeof indicator (seestd::feof()) onstdin. If the failure has been caused by some other error, sets theerror indicator (seestd::ferror()) onstdin.
Thestd::gets() function does not perform bounds checking. Therefore, this function is extremely vulnerable to buffer-overflow attacks. It cannot be used safely (unless the program runs in an environment which restricts what can appear onstdin). For this reason, the function was deprecated in C++11 and removed altogether in C++14.std::fgets() may be used instead.
#include <array>#include <cstdio>#include <cstring> int main(){std::puts("Never use std::gets(). Use std::fgets() instead!"); std::array<char,16> buf; std::printf("Enter a string:\n>"); if(std::fgets(buf.data(), buf.size(),stdin)){constauto len=std::strlen(buf.data());std::printf("The input string:\n[%s] is %s and has the length %li characters.\n", buf.data(), len+1< buf.size()?"not truncated":"truncated", len);}elseif(std::feof(stdin)){std::puts("Error: the end of stdin stream has been reached.");}elseif(std::ferror(stdin)){std::puts("I/O error when reading from stdin.");}else{std::puts("Unknown stdin error.");}}
Possible output:
Never use std::gets(). Use std::fgets() instead!Enter a string:>Living on Earth is expensive, but it does include a free trip around the Sun.The input string:[Living on Earth] is truncated and has the length 15 characters.
| reads formatted input fromstdin, a file stream or a buffer (function)[edit] | |
| gets a character string from a file stream (function)[edit] | |
| writes a character string to a file stream (function)[edit] | |
C documentation forgets | |
