Racket functions:

· (truncate num1) converts to decimal and chops after the decimal point. (truncate -2.5) is -2.

· (+ num1 num2) returns num1 + num2

· (remainder num1 num2) returns remainder after even division of num1 / num2.

o (cond [ test do-expression if true ]

[ test do-expression if true ]

[ else do-expression ] )

· (eq? list null) returns true if the list is empty

· (first list) returns the first item of the list

· (drop list 1) returns the list minus the first item of the list

C /C++ functions:

stdio.h:

void * malloc (int size ) returns a pointer to the newly allocated memory but will return null if cannot allocate.

FILE *fopen(const char *filename, const char *mode) returns a pointer to the FILE but will return null if cannot open

int fprintf(FILE *stream, const char *format, ...) returns the number of characters written

int fscanf(FILE *stream, const char *format, ...) returns the number of characters read

int scanf(const char *format, ...) returns the number of variables filled

int printf(const char *format, ...) returns the number of characters written

int puts(const char *str) returns the number of characters written

char *fgets(char *str, int n, FILE *stream) returns a pointer to a string of characters

int sprintf(char *str, const char *format, ...) returns the number of characters written

int sscanf(const char *str, const char *format, ...) returns the number of variables filled

string.h in C and <cstring> in C++

char *strcat(char *dest, const char *src) returns char *dest

char *strcpy(char *dest, const char *src) returns char *dest

char *strchr(const char *str, int c) returns a pointer to the first occurrence of c in str or a null pointer if not found.

int strcmp(const char *str1, const char *str2) returns 0 if equal, -number if str1 less than str2 and +number if str more than st2.

size_t strlen(const char *str)

char *strstr(const char *haystack, const char *needle) returns a pointer to the first occurrence of needle in haystack or a null pointer if not found.

ctype.h in C and <cctype> in C++

int tolower(int c) returns the lowercase version of c

int toupper(int c) returns the uppercase version of c

<string> in c++

• str.length – returns length as a property
• str[#] – lets you get straight to character index as though it were an array (no protection on out of bounds)
• str.at(#) – returns character in str at I (does have bounds checking)
• str.substr(position, length); - returns substring
• str.insert(position, str2); put str2 into str starting at position
• str.replace(position, length to be replaced, replacement string)
• str.find(str1, position) –returns index of str1 in str (position optional)
• str.c_str() – returns a cstring
• Helpful: getline(cin, str) : std::getline (std::cin,name); - input up to, not including linefeed from cin to str